The Lusi Mud Volcano

The story of the Lusi mud volcano in Indonesia is a fascinating mix of geology, health and human intrigue.

Let’s start with the geology.

The name ‘Lusi’ is a contraction of the Indonesian word ‘lumpur’, which means ‘mud’, and the place: Sidoarjo in East Java. The geology of the area is characterised by a mix of sedimentary deposition and tectonic activity, with the ground comprising of layers of limestone and long-buried marine mud, scattered with economically interesting pockets of gas and oil. Imagine a wide fault-bounded depression (‘graben’ in geo-speak) on the sea floor, filling up with deposits which are then squashed and uplifted by the Pacific ‘ring of fire’ tectonic plates jostling nearby, over the course (of course) of millions of years.

Fast forward to 2006: the area now forms part of the island of Java, and an oil and gas company, Lapindo Brantas, is out prospecting. Thanks to that geological squashing and uplifting, and the underlying sedimentary structure of layered mud, limestone, and impermeable clay, there’s lots of highly-pressurised grey goo sitting deep underground.

Apparently it’s common practice for exploratory boreholes to be protected with steel casing, which is deployed incrementally as the hole is drilled. For some reason, on the morning of May 29th the Lapindo Brantas team decided to dispense with such fripperies. At 5am their drill passed 2800m, and a small, ominous fart of steam and hydrogen sulfide gas erupted from the ground some 200m away from the well-head. Hot water and mud started to flow from the newly-formed vent. Two more vents appeared a few days later, and although these subsequent eruptions stopped, mud continued to ooze from the original site.

And it’s still oozing to this day.

By all accounts, the eruption wasn’t particularly spectacular. It’s just that the mud kept on coming, and coming, and coming. By December 2008, according the UN, 400 hectares of prime residential and agricultural land were covered. The mud continues to flow out of the vent at the rate of twenty olympic-sized swimming pools per day (I make that about 580 litres/second, for those averse to media-speak).

Although there’s something slightly comical— or incongruous at least— about the whole idea of a ‘mud volcano’, there have been some serious impacts on the local population.

More than 75,000 people have been displaced, and 10,000 homes, 35 schools, 31 factories, 65 mosques and one orphanage have been destroyed. Inundation of rice fields and fisheries have had an economic impact— with wiki earnestly describing how shrimp pond engulfment threatens the area’s status as the second biggest shrimp producer in Indonesia. The UN notes how the disaster has increased local unemployment levels.

There are health implications too. In November 2006, eleven people died in an explosion after mudflow-related subsidence broke a gas pipeline. The ongoing outflow threatens similar accidents in the future, as the emptying mud reservoir causes the overlying ground to slump and sink. 506 families still live in a refugee camp, and public health is threatened by irregular supplies of clean water and poor sanitation.

The cause of the mudflow has been hotly debated. The close proximity of the drilling team to the eruption site was difficult to ignore, and Lapindo came under scrutiny at an early stage. Unsurprisingly, the company fiercely contested the idea that they were to blame. What’s more, they had an alternative explanation: two days before the eruption, there had been a magnitude 6.3 earthquake 280km away in south central Java. The company maintained that underground cracks caused by this quake may have provided a protracted alternative route for the pressurised mud to reach the surface.

The controversy readily achieved the status of ‘international geological kerfuffle’. A paper published by a UK team at the University of Durham in 2007 seemed to shift the argument resoundingly in favour of ‘anthropogenic mud-level change’, although Lapindo had little difficulty finding geologists to lend support to their “it’s all in the rocks” hypothesis. A vote on the issue at a conference of petroleum geologists in South Africa supported the idea that Lapindo was at fault, although the legitimacy of the vote was subsequently called into question by the company’s band of tame ‘AMC’ contrarians.

Meanwhile the situation in Sidoarjo seems to have reached an uneasy stalemate, in human and in geological terms. Frenetic and ultimately unsuccessful initial attempts to halt the flow of mud— including the dropping of giant concrete balls into the vent— have given way to involved political discussion regarding reparations. An agreement in late 2008 resulted in the company paying compensation to some, though not all, of the affected local population— but without an admission of liability. Commentators have noted that various individuals in the government had financial interests in Lapindo. Giant earthworks contain the flood, and a channel has been constructed which diverts the overflow into a local river. Enterprising locals make up for lost income by taking visitors on tours round the site, and selling them DVD footage of the disaster.

In short: things ain’t as good as they were before, but life goes on.

The long-term future remains uncertain. The ooze may continue for ten years or longer, with experts anticipating further subsidence and caldera formation as the underground mud reservoir empties. Certainly, viewed with geology ‘deep time’ goggles, the incident is trivial. There have been mud volcanoes before— even human-induced ones. What sets the Lusi mud volcano apart is its location, in a densely settled part of one of the world’s most populous countries. The varying human interests, and how they collide with the hard realities of Earth processes, is what I find fascinating about the story. In some ways the situation could be considered a microcosm of a much larger drama playing itself out through the Anthropocene era. In this larger story— no prizes for guessing what I’m talking about here— none of us are bystanders.

Further reading

[Note: the initial draft was written nearly a year ago. There doesn’t seem to be much new on the interweb about it, so I’ve posted it in its original and probably outdated form]